Method of making an annular bearing



March 8, 1966 c. 5. WHITE 3,238,602

METHOD OF MAKING AN ANNULAR BEARING Original Filed March 14. 1961 ll i 4,7 ,7? u a E 5. if j [I [j 1 14:

@I W 1 E- Y4: 2252 I m2. 1; EE- E- E- @151 INVENTOR. C%4r%s -5. 14 17262 United States Patent C) 3,238,602 METHOD OF MAKING AN ANNULAR BEARINGCharles S. White, 35326 41st St., Palmdale, Calif. Continuation ofapplicatien Ser. No. 344,422, Feb. 12, 1964, which is a division ofapplication er. No. 95,684, Mar. 14, 1961. This application Apr. 23,1965, Ser.

3 Claims. (Cl. 29-1495) This invention relates to bearings andparticularly to a method for making a bearing in strip form which can beformed about a mandrel and finally sized directly thereto under heat andpressure. This application is a continuation of application Serial No.344,429 filed February 12, 1964, now abandoned, which was a division ofSerial No. 95,684, filed March 14, 1961, now abandoned.

It is one object of the invention to provide a method for making abearing from a flat bearing strip having a thin relatively rigid backingwith a low friction layer bonded to one face thereof by a formablebonding layer, the strip bearing being formed over a mandrel and heatand pressure applied thereto to soften the bonding layer to accuratelyconform the low friction layer to the surface of the mandrel, thebonding layer being hardened thereafter to rigidly anchor the lowfriction layer after it has been accurately sized.

It is another object of the invention to provide a method for making alarge, flat bearing strip of the type described above which can be cutup into smaller portions which, in turn, can be formed about a mandreland accurately sized by the application of heat and pressure to producefinal bearing shapes.

It is a further object of the invention to provide a method for making abushing-shaped liner or annulus having a low friction surface on theinner face thereof molded to an accurate internal diameter.

It is a still further object of the invention to provide a method formaking an accurately sized bearing liner that can be made by massproduction methods without machining.

It is a still further object of the invention to provide a method formaking a bearing liner adapted to fit over the ball of a stud and balland be accurately conformed to the surface of the ball when a socket isclamped about the bearing liner and ball.

It is a still further object of the invention to provide a method formaking a stud and ball having a bearing liner encompassing the ballthereof, the bearing liner having a low friction inner surfaceintimately engaging and conforming to the surface of the ball and a hardbacking layer on the outer surface thereof, the ball and bearing linerbeing adapted to be disposed within a socket in a manner to journal theball within the socket by the bearing liner.

It is a still further object of the invention to provide a method formaking a bearing liner which is accurately sized, economical tomanufacture and rugged and effective in use.

Other objects and features of novelty of the invention will bespecifically pointed out or otherwise become apparent when referring,for a better understanding of the invention, to the followingdescription taken in conjunction with the accompanying drawings wherein:

FIGURE 1 is a broken plan view of a bearing in strip form embodyingfeatures of the present invention;

FIGURE 2 is an enlarged sectional view of the structure illustrated inFIGURE 1, taken along the line 2-2 thereof;

FIGURE 3 is an enlarged sectional view similar to that of FIGURE 2before the bonding layer and low friction layer are added to the backinglayer;

FIGURE 4 is an enlarged sectional view similar to that of FIGURE 3 afterthe bonding layer has been applied to the backing layer;

FIGURE 5 is a sectional view of a shaped mandrel having the stripbearing of FIGURE 1 shaped to the surface thereof;

IGURE 6 is a sectional view of a sizing mandrel having the strip bearingof FIGURE 1 encircling the surface thereof;

FIGURE 7 is an enlarged sectional view similar to that of FIGURE 2illustrating a modification of the in vention;

FIGURE 8 is a plan view similar to that of FIGURE 1 illustrating anothermodification of the invention;

FIGURE 9 is a plan view of a control arm for an automotive vehiclehaving a ball joint embodying features of the present invention securedbeneath the apex thereof;

FIGURE 10 is a sectional view of the structure illustrated in FIGURE 9,taken along the line 1010 thereof;

FIGURE 11 is a plan view of a strip bearing illustrating another form ofthe invention;

FIGURE 12 is a sectional view of apparatus for forming a bearing linerabout a ball of a stud and ball embodying other features of theinvention.

Referring to FIGURES 1 and 2, a strip bearing 20 embodying features ofthe present invention is illustrated which comprises an elongated,relatively thin, backing layer 22 having a low friction layer 24 securedto one face thereof by a bonding layer 26. The backing layer 22 ispreferably made of metal or other similar material which can provide arelatively rigid backing for the low friction layer and still enable thestrip bearing 20 to be formed about a mandrel as illustrated in FIGURE 5and as will be described in greater detail hereinafter.

The low friction layer 24 can be any suitable low friction materialwhich will provide a low friction face for the strip bearing 20 after ithas been formed into a bushing or the like as illustrated in FIGURES 5and 6. The bonding layer 26 can be any suitable plastic material thatcan bond the low friction layer 24 to the backing layer 22 and besoftened under heat and pressure thereafter to accurately conform thelow friction layer to the surface of one of the mandrels in FIGURES 5and 6, as will also be described in greater detail hereinafter.

Referring to FIGURE 3, the backing layer 22 as illustrated before thelayers 24 and 26 are bonded thereto. All four upper edges of the backinglayer are rounded as indicated by the numerals 28, and the bonding layer26 is bonded to the upper surface of the backing layer and extends overthe rounded corners thereof as illustrated in FIGURE 4. The low frictionlayer 24 is thereafter bonded to the bonding layer 26 so that it alsocovers the rounded corners 28.

After the low friction layer 24 has been bonded to the bonding layer 26,the strip bearing can then be formed about a shaping mandrel 30 asillustrated in FIGURE 5 to form the strip bearing into a bushing withthe ends 32 of the strip bearing abutting against one another. Ifdesired, the strip bearing can be made in one long strip which can becut up into predetermined shorter length adapted to fit over themandrel. Once the strip bearing is shaped about the mandrel 30, themetal backing layer 22 will retain the strip bearing in the shape of abushing which can then be removed and disposed over a somewhat largersizing mandrel 34, as illustrated in FIGURE 6, with the ends 32 spacedslightly apart. Heat and pressure are then applied to the bushing tosoften the bonding layer 26 until it yields to close the gap between theends 32 and accurately conforms the low friction layer 24 to the exactdiameter of the sizing mandrel 34.

The ends 32 are then preferably locked together by suitable means andthe bonding layer 26 hardened so that the strip hearing will retain thisfinal bushing shape having a very accurately sized internal diameter.The bushing is thereafter slipped off the end of the mandrel 34 and usedfor journaling shafts having the same diameter as the sizing mandrel 34.With this method, a large number of bushing-shaped strip bearings can beformed with mass production techniques which are each very accuratelysized to an exact inside diameter. To obtain the desired diameter,-thelow friction layer 24 is preferably made relatively thin, a thickness ofseveral thousandths of an inch being preferred. The bonding layer 26need only be thick enough to provide the desired conformation and, ofcourse, must soften at a lower temperature than the low friction layerand backing layer so that bonding layer provides the conformation andnot the other layers. However, it is also within the purview of theinvention to provide a bonding layer 26 that also has low frictionproperties, in which even the low friction layer could be eliminatedwith the bonding layer itself providing the low friction surface afterit has conformed to the mandrel and hardened.

By rounding the corners 28 of the strip bearing as described above, theends 32 can be abutted together in a more satisfactory manner when thebushing is finally sized and the rounded corners at the ends of thebushing enable the bushing to be freely slipped on and off the shaftwhich it is to support without damaging the ends of the low frictionlayer 24. If desired, the bonding layers 26 and low friction layer 24can be carried completely around the corners 28 of the backing layer 22as at 36 and 38, respectively, in FIGURE 7 to cover all but the bottomsurface of the backing layer 22 with the layer of low friction material24.

As stated previously, the low friction layer 24 can be any low frictionmaterial which will provide a suitable bearing surface for the finalbearing. Examples of suitable low friction materials arepolytetrafluoroethylene resins, nylon, polyethylene molding compoundsand monochlorotrifluoroethylene resins, the first and last resins beingcommonly referred to by the trade names Teflon and Kel-F, respectively.However, the preferred type of low friction layer comprises a thin layerof Teflon fibers either secured to the bonding layer 26 as a layer offlocking, felting or Woven into a fabric layer, Teflon having far superior cold flow characteristics when in fiber form than when in solidsheet form. Reference is made to White Patent 2,885,248 and ReissuePatent 24,765 for a detailed description of two ways of bonding Teflonfabric to the bonding layer 26.

As stated previously, the bonding layer 26 can be any thermosetting orthermoplastic material which will soften and yield at a lowertemperature than the low friction layer 24 so that when heat andpressure are applied in the final sizing of the bushing, as described inconnection with FIGURE 6, the bonding layer 26 will yield to accuratelyconform the low friction layer 24 to the size of the mandrel, and canthereafter be hardened to retain the low friction layer in the final,accurate cylindrical shape. Suitable thermosetting resin materials arepreferred for use as the bonding layer 26 since there are manythermosetting materials which are stronger and enable the completedbushing to support greater loads. Further, when a thermosetting resinmaterial is used as the bonding layer 26, it can be partiallypolymerized or cured after bonding the low friction layer 24 to thebacking layer 22 as illustrated in FIGURE 4 to provide a strip bearingwhich can be stored indefinitely in its hardened partially cured stripform. When it is desired to form the final bushing from the partiallycured strip bearing, the strip bearing can be shaped as described inconnection with FIG- URE 5, and finally sized under heat and pressure asillustrated and described in connection with FIGURE 6, the thermosettingbonding layer 26 softening under heat and pressure to conform the layerof low friction material accurately to the surface of the mandrel 34before it is finally cured and hardens to rigidly retain the lowfriction layer in its exact final shape.

Referring to FIGURE 8, la modification of the strip bearing 29 isillustrated wherein a circular tongue 40 is provided on one end of thestrip bearing 26 and a corresponding groove 42 is provided in the otherend thereof. When the bearing is finally sized about the sizing mandrel34, the tongue 40 can be fitted within the groove 42 to interlock theends 32 together and provide a smooth flush outer surface for theannulus so formed.

In each of the embodiments described, the bushing is preferably used asa liner for the body or member which is to support the shaft and wouldpreferably be secured with a suitable aperture in the body or memberthrough which the shaft extends. Consequently, the ends 32 need notnecessarily be locked together, but can be abutted together within theaperture (since they are abutted together when finally shaped about thesizing mandrel 34) and still retain their accurate internal diameter.

Referring to FIGURES 9 and 10, a control arm 44 is illustrated havinglegs 46 on the inner end thereof adapted to be pivotally mounted on theframe of an automotive vehicle for supporting a front wheel of thevehicle. A ball joint 48 is secured to the underside of the pivoting endthereof and has a stud 49 adapted to be connected to the front wheel. Asemispherical dome 50 is formed on the pivoting end of the control armto provide the upper half of the socket for a ball 56 and a generallytruncated stamping 52 having radially extending flanges 54' provides thelower half of the ball joint, the flanges 54 being welded or otherwisesuitably secured to the underside of the control arm 44. The ball 56 ofthe ball joint is journaled within the socket by a bearing liner 58which comprises the same three layers as the strip bearingZtl, namely,the low friction layer 24, the bonding layer 26 and the backing layer22. The bearing liner 58 is formed about the ball 56 in a mannersomewhat similar to the way the strip bearing 20 was formed about theshaping mandrel of FIGURE 5. The ball with the liner thereabout is thenpositioned within the socket between the dome 50 and the truncatedspherical bottom stamping 52. The bearing liner is made slightlyoversize so that the flange 54 of the bottom stamping 52 do not quitemeet the underside of the control arm. Heat is then applied to the balljoint to soften the bonding layer 26 and the flanges 54 are urged intoabutting engagement with the control arm to exert radial pressure on thebearing liner 58 to cause the bonding layer 26 to yield and accuratelyconform the low friction layer 24 to the surface of the ball 56. Afterthe bonding layer 26 is hardened, the low friction layer 24 is supportedin position to intimately and accurately engage the surface of the ballto journal the ball in the socket. Normally, the greater frictionbetween the backing layer 22 and socket Will prevent the liner fromshifting relative to the socket, but if desired, the liner can also bepositively fixed against shifting relative to the socket by any suitablemeans, such as by welding, or by mechanically interlocking the liner andsocket together.

Referring to FIGURE 11, one way of forming the bearing liner 58 isillustrated. In this example, the hearing liner is first formed in afiat, star-shaped bearing 60 having a plurality of points or projections62. The flat bearing 60, of course, comprises the same three layers asthe bearing strip 20 and, as illustrated in FIGURE 11, the backing layer22 is on the upper side. The points 62 are proportioned so that thebearing 60 can be fitted over the dome of the ball and formed about theball with the projections engaging the underside of the ball and nestingsnugly together. Once formed over the ball in this manner, the ball withthe liner thereon can be fitted between the dome 5i and stamping 52 andheat and pressure applied as previously described to conform the lowfriction layer 24 accurately. to the surface of the ball 56. If desired,the bonding layer 26 can be made from a thermosetting material and canbe partially cured when the bearing 60 is in its fiat shape asillustrated in FIGURE 11, and finally cured after the bearing liner hasbeen formed over the ball and the heat and pressure is applied. Also, ifthe low friction layer 24 comprises a fabric material it can be wovenwith an elastic or expansible weave to facilitate its formation aboutthe dome of the ball 56.

Referring to FIGURE 12, a split die apparatus is illustrated whichprovides another way of forming the bearing liner 58 for a ball joint.This apparatus comprises a split die 64 having two halves 66 and 68fitted together over the hall of a stud and ball with a sufiicientclearance therebetween to provide a cavity 70 between the surface of theball and the die elements 60 and 68. In this construction, the lowfriction layer 24 and bonding layer 26 are disposed about the ball 56and a suitable backing material is injected under pressure through anaperture 72 in the upper portion of the die to completely fill the spacewithin the cavity 70, the lower portion of the die sealing about thejuncture of the stud and ball to prevent the material from escaping.After the material is hardened, it provides the backing layer 22 for thebearing liner 58. The die elements 66 and 68 can then be split apart andthe ball with the bearing liner 58 thereon removed and inserted betweenthe dome 50 and lower stamping 52 of the ball joint 48. Heat andpressure can then be applied as previously described to finally form thelower friction layer 24 to the surface of the ball 58.

If desired, the low friction layer 24 can be finally formed to thesurface of the ball 56 by the heat and pressure of the injected materialwhich will retain the low friction layer in accurate surface engagementwith the ball after it hardens. The bearing liner can then be merelyclamped between the dome and stamping 52 without providing additionalheat for forming the low friction layer 24 to the ball.

While it will be apparent that the preferred embodiments hereinillustrated are well calculated to fulfill the objects above stated, itwill be appreciated that the inven tion is susceptible to modification,variation and change without departing from the the proper scope of fairmeaning of the subjoined claims.

The embodiments of the invention in which an. exelusive property orprivilege is claimed are defined as follows:

1. The method of forming a bearing comprising the steps of applying athermosetting bonding resin and a low friction organic polymeric fibermaterial to a flat metal backing member whereby said metal backingmember is coated with a low friction surface layer, cutting from saidcoated flat metal member a strip of predetermined length having lockingmeans formed at the ends thereof, bending said strip and securing saidlocking means together to form an annulus with said low friction layeron the inner surface thereof and with said inner surface sized topredetermined diameter, and hardening said resin while under pressure byapplying heat thereto.

2. The method as set forth in claim 1 and including the further step ofmachining the outside surface of said annulus to predetermined diameter.

3. The method as set forth in claim 1 wherein said fiber material is inthe form of a cloth.

No references cited.

WHITMORE A. WILTZ, Primary Examiner.

1. THE METHOD OF FORMING A BEARING COMPRISING THE STEPS OF APPLYING ATHERMOSETTING BONDING RESIN AND A LOW FRICTION ORGANIC POLYMERIC FIBERMATERIAL TO A FLAT METAL BACKING MEMBER WHEREBY SAID METAL BACKINGMEMBER IS COATED WITH A LOW FRICTION SURFACE LAYER, CUTTING FROM SAIDCOATED FLAT METAL MEMBR A STRIP OF PREDETERMINED LENGTH HAVING LOCKINGMEANS FORMED AT EHE ENDS THEREOF, BENDING SAID STRIP AND SECURING SAIDLOCKING MEANS TOGETHER TO FORM AN ANNULUS WITH SAID LOW FRICTION LAYERON THE INNER SURFACE THEREOF AND WITH SAID INNER SURFACE SIZED TOPREDETRMINED DIAMETER, AND HARDENING SAID RESIN WHILE UNDER PRESSURE BYAPPLYING HEAT THERETO.